P2499Effects of aerobic and resistance exercise on skeletal muscle of infarcted rats

Background Skeletal muscle changes contribute to reduced physical performance after myocardial infarction (MI). Exercise has been recommended to stable patients. However, the effects of resistance exercise after MI are not clear. We compared the effects of aerobic and resistance exercise initiated during compensated cardiac remodeling in infarcted rat gastrocnemius muscle. Methods Three months after MI induction, Wistar rats were divided into four groups: Sham (n=20); sedentary MI (MI-S, n=9); aerobic exercised MI (MI-A, n=9); and resistance exercised MI (MI-R, n=13). Exercised rats trained three times a week for 12 weeks on a treadmill or ladder. Energy metabolism, oxidative stress markers, and antioxidant enzyme activities were assessed by spectrophotometry. Satellite cells activation markers (MyoD, NCAM, and myosin heavy chain neonatal isoform) were assessed by immunofluorescence or Western blot (Pax-7). Statistical analysis: ANOVA or Mann Whitney. Results Physical aerobic capacity was greater in MI-A and strength gain higher in MI-R. Cardiac structures and left ventricular function evaluated by echocardiogram did not differ between infarcted groups. Histological analysis showed that MI size and gastrocnemius cross sectional area did not differ between infarcted groups. Oxygen reactive species production was higher in MI-S than Sham and lipid hydroperoxide concentration was lower in MI-A than the other groups. Catalase activity was higher and glutathione peroxidase lower in infarcted groups than Sham. Superoxide dismutase activity was higher in Sham and MI-R than MI-S. Skeletal muscle metabolism enzyme activity did not differ between groups, except for increase pyruvate kinase in MI-S against the other groups, and β-hydroxyacyl CoA dehydrogenase in MI-S against Sham. Satellite cell activation and protein expression of MAPK and NF-kB did not differ between groups. Conclusion Aerobic and resistance exercise respectively improves physical capacity and muscle strength without changing echocardiographic parameters of infarcted rats. Myocardial infarction increases oxygen reactive species production and changes antioxidant enzyme activity and glucose and fatty acid metabolism. Aerobic exercise is superior to resistance exercise against oxidative stress reducing muscle lipid hydroperoxide concentration and attenuating change in glutathione peroxidase activity. Acknowledgement/Funding Financial support: Fapesp, CNPq, Capes, and UNESP

The effect of zeolite on oxidant/antioxidant status in healthy dairy cows

This study was conducted to evaluate the effect of dietary zeolite (clinoptilolite) supplementation on the oxidative/antioxidative status on plasma in healthy dairy cows. Twenty dairy cows were divided into two groups of 10. Control group was fed the basal ration for 60 days. Zeolite group was fed the basal ration supplemented with 2.5% zeolite daily. To evaluate the oxidative and antioxidative status comprehensively, indicators such as total oxidant status, oxidative stress index, total antioxidant status, lipid hydroperoxide, total free sulphhydryl groups, ceruloplasmin concentrations, arylesterase, paraoxonase-1 and catalase activities were measured in plasma. Lipid hydroperoxide concentration was significantly (P< 0.05) decreased from 6.21 ± 0.94 to 4.90 ± 1.05 mmol H2O2Eq/l by zeolite supplementation. However, no significant effect was observed on the antioxidant and other oxidant indicators. In conclusion, although zeolite decreased the lipid hydroperoxide concentration, it cannot further strengthen antioxidant defense system in healthy dairy cows.

Effect of alloxan on glutathione system and oxidative protein modification in adipocytes of rats at experimental diabetes

There was carried out a research of the development of oxidative stress, the condition of glutathione dependant system of antioxidant protection in adipocytes of epididymal adipose tissue of rats when injecting alloxan. The development of oxidative stress in adipocytes was characterized by the increase of lipids hydroperoxide concentration, products reacting with thiobarbituric acid, and the increase of carbonylderived protein. Redox-condition in adipocytes was considerably changing that was specified by the decrease of the content of the reduced form of glutathione and tendency to the increase of glutathione disulfide content, decrease of ratio between reduced and oxidized forms of threepeptide. Damage of protein molecule at oxidative stress may lead to the abnormality of transduction of insulinic signal and appearance of insulin resistance in adipose tissue.